If you want to compare participation numbers then count all the people that go to a driving range once or places like Topgolf. Bowling counts the 3 year olds that use a ramp and bumpers.
I understand numbers like these are never completely accurate. Hell, should we count Putt-Putt? What about the guys who don't play but putt at Golfsmith? I even have friends who don't bowl but love Wii bowling.
I just thought it was interesting to see on average, there are supposedly 10,000 unique bowlers per center and almost 1,600 unique golfers per golf course. Bowling centers obviously can handle more bowlers than a golf course can handle golfers, I was just surprised to see the difference.